AU2006100400A4 - A Component for an Engine Mount - Google Patents

Description

A COMPONENT FOR AN ENGINE MOUNT Field of the Invention.

The present invention relates to engine mounts and particularly to components for engine mounts and devices for vibration control.

Background Art.

Engine mounts are known in the art. The general function of an engine mount is to facilitate attachment between the engine and the vehicle or vessel which the engine powers.

It is known that engines when in operation, create vibration as well as large amounts of torque. Therefore, engine mounts have been designed to isolate the vibration of the engine from the remainder of the vehicle or vessel and also to control the movement of the engine caused by the mechanical action and output forces of the engine, relative to the vessel, vehicle or installation structure in which the engine operates. As such, the engine mount usually includes a vibration damping resilient member interposed between two members in a vibration transmitting system so as to dampen the vibration transmitted between the two members.

One such vibration dampening member is disclosed in United States Patent No. 6,858,675. In that document, prior art attempts to solve problems associated with the vibration dampening system include provision of a vibration damping rubber member for vibration transmitting systems involving different kinds of vibrations having different frequencies. The vibration damping rubber member used in these systems is required to exhibit a relatively low degree of dynamic spring stiffness with respect to input vibrations having comparatively high frequencies of 100 Hz or higher, and to exhibit a relatively high damping effect with respect to input vibrations having comparatively low frequencies of about 10-20 Hz. This solution proposed to use natural rubbers (NR) which are suitable for reducing the dynamic spring stiffness of the vibration damping rubber members, and add a carbon black to the natural rubbers, to increase the damping effect of the vibration damping rubber members.

There have also been proposed, fluid-filled vibration damping rubber members, as improvements in the construction rather than the material. Generally, such fluid-filled vibration damping rubber members use an elastic body formed of a rubber composition in which a plurality of fluid chambers are formed in fluid communication with each other through orifice passages (restricted fluid passages).

These fluid-filled vibration damping rubber members are arranged to exhibit desired vibration damping characteristics depending upon respective frequency bands of the input vibrations; on the basis of resonance of a fluid flowing through the orifice passages. Accordingly, those fluid-filled vibration damping rubber members are inevitably complicated in construction, with a relatively large number of components, and suffer from potential problems of a relatively high cost and considerable difficulty of manufacture.

The vibration damping rubber members are required to have a relatively high degree of hardness, in view of their applications in which the rubbers should withstand a relatively large load, for instance. This requirement is conventionally satisfied by using a rubber composition which contains a diene-based rubber material such as a natural rubber and additives such as a carbon black.

The addition of such additives including the carbon black makes it possible to increase the hardness and the vibration damping effect of the vibration damping rubber member, but inevitably results in an undesirable increase in the dynamic spring stiffness.

Therefore, in light of the various problems associated with vibration damping members, what is required is a simple, easily manufactured component which has the desire properties.

It will be clearly understood that, if a prior art publication is referred to herein, this reference does not constitute an admission that the publication forms part of the common general knowledge in the art in Australia or in any other country.

Summary of the Invention.

The present invention is directed to a component for an engine mount, which may at least partially overcome at least one of the abovementioned disadvantages or provide the consumer with a useful or commercial choice.

In one form, the invention resides in a component for an engine mount used to mount the engine relative to a mounting surface and having a main axis, the component located between the mounting surface and the engine, the component including a first part located adjacent the mounting surface and having a first hardness rating and a second part located adjacent the engine and having a second hardness rating, wherein the second hardness rating is lower than the first, the second part providing dampening to forces in the direction of the main axis and the first part providing rigidity to resist forces applied perpendicularly to the main axis.

The component of the present invention will typically be identified as a flexible top core of an engine mount. The engine mount may be utilised in any situation that a standard engine mount can be used. Typically, engine mounts include a rigid base member for mounting to a mounting surface, a upstanding stud assembly adapted to attach to the engine and a dampening assembly, usually a dampening member located between the base member and the stud assembly.

The stud assembly is generally an upstanding threaded member which extends through an annular flexible top core of the engine mount. Normally there is a plate member provided about the threaded member and over the flexible top core to spread the force applied over the area of the top core and to provide compressive force onto the to core.

The top core component includes a first part located adjacent the mounting surface and having a first hardness rating and a second part located adjacent the engine and having a second hardness rating.

The second hardness rating is lower than the first, so that the second part being more resilient or flexible than the first part allows the core to dampen forces applied to the top core in the direction of the main axis. The first part having a higher hardness rating, provides the core with rigidity to resist forces applied perpendicularly to the main axis and decreases rocking or similar motion imparted on the mount by the engine.

The first part of the top core is preferably cylindrical in shape with an opening through the first part. The opening will typically allow the stud of the stud assembly, which attaches the engine, to pass through the top core and be closely received therein. The cylindrical first part is typically approximately between 10-30 mm in height although the height of the first part will differ depending upon application.

The diameter of the first part of the top core will also preferably differ depending upon application and will typically be between 50mm and 100mm but more likely to be between 60 to The second part of the top core will typically include a frustoconically shaped portion, converging upwardly away from the first part. The second part of the

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Stop core will typically be of larger diameter than the first part. The first part will preferably be separated from the frustoconical portion by an outwardly extending wall which is coplanar with the upper edge of the first portion and then an upwardly extending wall portion. The second part of the top core therefore will preferably have a substantially cylindrical portion below the frustoconical portion and above the first part. Preferably, the opening through the first part extends through the second part as well and therefore may be a channel through the entire top core.

The engine mount in which the component of the present invention is INO used comprises of a polymer base for mounting to a mounting surface, the component, which in the preferred embodiment, is a copolymer top flexible core which is situated in a recess in the top of said base, and a polymer flexible rebound core situated in the underside of the base, a steel stud assembly passing through the two said flexible cores, a steel insert assembly for the stud assembly to screw down into and a top steel washer to fit onto of the mount assembly to provide compression to the top core. A locking nut on the stud assembly retains the top washer and top flexible core and flexible rebound core together.

The engine mount is designed as such that the base is bolted down to an installation structure. The engine is then attached to the mount by way of the stud assembly. The engine mount then behaves as a spring, allowing axial movement of the engine mass to isolate the vibration from the installation structure.

The spring rate and hence efficiency at which the engine mount operates is dictated primarily by the copolymer flexible top core and secondly by the bottom flexible core. The top core compression rate is determined mainly by material composition and shape profile. The bottom rebound core controls the rate at which the mount or steel stud assembly may rebound.

The forces placed specifically upon the top flexible copolymer core act in three axis, vertically (or axially along the main axis of the engine mount which is typically coaxial with the steel stud assembly), in a thrust direction (forward or reverse) and laterally (sideways).

The flexible top core of the present invention is designed and will be manufactured of a suitable material to have a defined deflection for a given force.

This defines the spring rate in the direction at which the force is applied.

As an engine mount, it is a desired requirement according to the present invention to have different spring rates according to the direction of the applied force.

The top core of the invention will typically be manufactured in a variety of forms with different materials used to give variations of dampening effects in the different axial directions. For example, the first part will normally have a Shore Hardness rating of approximately 95 in all configurations. However, the top core may be manufactured with the Shore Hardness of the second part of one of either 40, 55, 60, 65, 70, 75, 80, 85 or 90 on top of the 95 Shore Hardness first part. This will allow a user to choose the amount of dampening which is provided by the selection of the top core. Preferably, the various combinations of materials may be colour-coded to provide reliable and easy identification of the material properties of the core by visual inspection.

The first material will typically be at least 95 Shore A hardness and the second material a hardness of less than Shore Hardness 95. The advantages of the invention are derived by having the two materials of different hardness in the same core.

According to a particularly preferred embodiment, the top flexible copolymer core is preferably manufactured of two different materials with two types of Shore A Hardness, in a single core component. Preferably, the base of the component of said core is a 95 Shore Hardness polymer, and the top or upper component of the core is composed of a different Shore Hardness polymer, the hardness of which is chosen from the range of between 40 through to 90 Shore Hardness. This combination provides increased resistance higher spring rate) to force applied in the direction of the lateral and/or thrust axis, whilst allowing a lower (or softer spring rate) in the main axial direction (typically vertically)to give adequate vibration isolation from the energy source the engine).

According to this embodiment, the top flexible copolymer cores are preferably manufactured by firstly pouring the 95 Shore A hardness material into a heated mould, then the second (varying between 40 to 90 Shore hardness) polymer material is poured over the 95 Shore hardness polymer. The two polymers preferably formn an integral bond and a unitary, copolymer product. The said copolymer is then cured in a heated oven to complete the product for assembly. Of course, a person skilled in the art will realise that the two material core can be formed by pouring the 6 softer of the two materials into the mould first and then adding the harder of the two materials.

There may further be a bottom or rebound core provided in the engine mount as well. This bottom core may be a copolymer core manufactured of two materials as the top core is, or may be of a single material. The bottom core will also preferably have an opening extending through the core again for the stud of the stud assembly. The bottom core is typically located below the base of the engine mount.

Brief Description of the Drawings.

Various embodiments of the invention will be described with reference to the following drawings, in which: Figure 1 is a side elevation view of an adjusting stud engine mount with vibration isolation action according to a preferred embodiment of the present invention.

Figure 2 is a top view of the engine mount illustrated in Figure 1.

Figure 3 is a side elevation view of a component for an engine mount with vibration isolation action according to a first preferred embodiment of the present invention.

Figure 4 is a side elevation view of a component for an engine mount with vibration isolation action according to a second preferred embodiment of the present invention.

Detailed Description of the Preferred Embodiment.

According to a preferred embodiment of the invention, a component for an engine mount, as illustrated in Figures 1 and 2 is provided.

The component is to be used to mount an engine relative to a mounting surface and as such is located between the mounting surface and the engine. The component of the present invention is normally referred to as a flexible top core The engine mount, a preferred form of which is illustrated in Figures 1 and 2, can be utilised in any situation that a standard engine mount can be used.

The preferred engine mount includes a rigid base member 11 for mounting to a mounting surface via mounting openings 15, a upstanding stud assembly 12 adapted to attach to the engine (not shown) and a dampening assembly, usually a dampening member or top core 10 located between the base member 11 and the stud assembly 12. The engine mount is designed as such that the base member 11 O 7 is bolted down to an installation structure. The engine is then attached to the mount by way of the stud assembly 12. The engine mount then behaves as a spring, allowing axial movement of the engine mass to isolate the vibration from the installation I structure.

The stud assembly includes an upstanding threaded stud member 13 which extends through an annular flexible top core 10 of the engine mount. Normally zthere is a plate member 14 provided about the threaded member 13 and over the flexible top core 10 to spread the force applied over the area of the top core 10 and to IND provide compressive force onto the to core 10. The engine mount has a main axis which is basically coaxial with the upstanding threaded stud member 13.

The top core 10 of the preferred embodiment of the invention as illustrated in Figures 3 and 4, includes a first part 16 located adjacent the base of the engine mount and having a first hardness rating, and a second part 17 located adjacent the engine and having a second hardness rating, wherein the second hardness rating is lower than the first.

As the hardness rating of the second part 17 is lower than the first, the second part 17 is therefore more resilient or flexible than the first part 16 allowing the core 10 to dampen forces applied to the top core 10 in the direction of the main axis.

The first part 16 having a higher hardness rating, provides the core with rigidity to resist forces applied perpendicularly to the main axis and decreases rocking or similar motion imparted on the mount by the engine.

As illustrated in Figures 3 and 4, the first part 16 of the top core 10 is cylindrical in shape with an opening 18 through the first part 16. The opening 18 allows the threaded stud 13 of the stud assembly, which attaches the engine, to pass through the top core 10 and be closely received therein. According to the preferred embodiment illustrated, the cylindrical first part 16 is approximately 15 mm in height.

The diameter of the first part 16 of the top core 10 will also preferably differ depending upon application and will typically be between 50mm and 100mm but more likely to be between 60 to The second part 17 of the top core 10 includes a frustoconically shaped portion 19, converging upwardly away from the first part 16. The second part 17 of the top core is larger in diameter than the first part 16. The first part 16 is separated from the frustoconical portion 19 by an outwardly extending wall 20 which is coplanar with the upper edge of the first portion 16 and then an upwardly extending wall portion 21. The second part 17 of the top core 10 therefore has two parts, a substantially cylindrical portion below a frustoconical portion 19, both portions located above the first part 16. The opening 18 through the first part 16 extends through the second part 17 as well and therefore is a channel through the entire top core The spring rate and hence efficiency at which the engine mount operates is dictated primarily by the copolymer flexible top core 10. The top core compression rate is determined mainly by material composition and shape profile.

The forces placed specifically upon the top flexible copolymer core act in three axis, vertically (or axially along the main axis of the engine mount which is typically coaxial with the stud assembly 12), in a thrust direction (forward or reverse) and laterally (sideways).

The flexible top core 10 of the preferred embodiment is designed and manufactured of suitable materials to have a defined deflection for a given force. This defines the spring rate in the direction at which the force is applied.

The top core 10 will be manufactured in a variety of forms with different materials used to give variations of dampening effects in the different axial directions. For example, the first part 16 will normally have a Shore Hardness rating of approximately 95 in all configurations. However, the top core 10 may be manufactured with the Shore Hardness of the second part 17 of either 40, 45, 50, 65, 70, 75, 80, 85 or 90 on top of the 95 Shore Hardness first part 16. This will allow a user to choose the amount of dampening which is provided by the selection of materials making up the top core 10. Preferably, the various combinations of materials may be colour-coded to provide reliable and easy identification of the material properties of the core by visual inspection.

This combination provides increased resistance higher spring rate) to force applied in the direction of the lateral and/or thrust axis, whilst allowing a lower (or softer spring rate) in the main axial direction (typically vertically)to give adequate vibration isolation from the energy source the engine).

According to this embodiment, the top flexible copolymer cores are preferably manufacture by firstly pouring the 95 Shore A hardness material into a heated mould, then the second (of a hardness between 40 to 90 Shore hardness) polymer material is poured over the 95 Shore hardness polymer. The two polymers preferably form an integral bond and a unitary, copolymer product. The said copolymer is then cured in a heated oven to complete the product for assembly.

There may further be a bottom or rebound core provided in the engine mount as well. This bottom core may be a copolymer core manufactured of two materials as the top core is, or may be of a single material. The bottom core will also preferably have an opening extending through the core again for the stud of the stud assembly. The bottom core is typically located below the base of the engine mount.

The bottom core controls the rate at which the mount or steel stud assembly may rebound relative to the base member 11.

In the present specification and claims (if any), the word "comprising" and its derivatives including "comprises" and "comprise" include each of the stated integers but does not exclude the inclusion of one or more further integers.

Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearance of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more combinations.

In compliance with the statute, the invention has been described in language more or less specific to structural or methodical features. It is to be understood that the invention is not limited to specific features shown or described since the means herein described comprises preferred forms of putting the invention into effect. The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims (if any) appropriately interpreted by those skilled in the art.

Claims (4)

1. A component for an engine mount used to mount the engine relative to a mounting surface and having a main axis, the component located between the mounting surface and the engine, the component including a first part located adjacent the mounting surface and having a first hardness rating and a second part located adjacent the engine and having a second hardness rating, wherein the second hardness rating is lower than the first, the second part providing dampening to forces in the direction of the main axis and the first part providing rigidity to resist forces applied perpendicularly to the main axis.

2. An engine mount including a base for mounting to a mounting surface and having a recess therein, a top core component including a first part located adjacent the mounting surface and having a first hardness rating and a second part located adjacent the engine and having a second hardness rating which is situated in the recess in said base, and a flexible rebound core situated in the underside of the base, a stud assembly passing through the two said cores, and a top washer to fit onto the stud assembly to provide compression to the top core.

3. A component according to claim 1 wherein the first part is cylindrical in shape with an opening through the first part and the second part of the top core includes a frustoconically shaped portion of larger diameter than the first part and converging upwardly away from the first part.

4. A component according to claim 3 wherein the first part is a 95 Shore Hardness polymer, and the second part is composed of a different Shore Hardness polymer, chosen from within the range of from 40 to 90 Shore Hardness. A method for forming a dampening component for an engine mount including the steps of inserting a material of at least 95 Shore A hardness into a heated mould, inserting a second material with a hardness of less than Shore Hardness over the 95 Shore hardness polymer, allowing the two materials to form an integral bond and a unitary, copolymer product, having a first part having a first hardness rating and a second part having a second hardness rating, wherein the second hardness rating is lower than the first, the second part providing dampening to forces in the direction of the main axis and the first s 11 O part providing rigidity to resist forces applied perpendicularly to the main axis. and curing the copolymer product in a heated oven. Dated this 15th day of May 2006 IsoFlex Technologies Pty Ltd By its patent attorneys SCULLEN CO 0,